Background: Colorectal cancer (CRC) is the second commonest cause of cancer-related death in the United Kingdom and the third commonest cancer worldwide. Preoperative chemoradiotherapy is widely used to down-stage rectal tumours and improve surgical outcomes; however, its long-term molecular consequences on normal rectal tissue remain poorly understood. Objective: To identify molecular changes in gene and protein expression in normal rectal tissue of CRC patients who received preoperative chemoradiotherapy compared to those who underwent surgery alone. Methods: Normal rectal muscle-layer tissue samples were collected from 14 patients (chemoradiotherapy group, n=7; surgery-only control group, n=7). RNA was extracted and used to synthesise cDNA for RT-qPCR analysis of 15 target genes involved in autophagy, oxidative stress, neuro-axonal transport, angiogenesis, and tissue elasticity. Protein expression of GPX3 was assessed by western blotting. Statistical analysis was performed using the Mann-Whitney U test. Results: Variable changes in gene expression were observed between the two groups, most notably in ATG7, CAT, PRCKD, and GPX4. None of these differences reached statistical significance (p > 0.05), although CAT showed a trend (p=0.073). GPX3 gene expression demonstrated a statistically significant difference (p=0.024), but western blotting revealed no corresponding significant change in GPX3 protein expression (p=0.80). Conclusion: Preoperative chemoradiotherapy appears to alter gene expression in the oxidative stress pathway in normal rectal tissue, though these changes were not statistically significant due to the small sample size. Larger studies with quantitative protein analysis are warranted to confirm these findings.